1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998 Michael Smith 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * The unified bootloader passes us a pointer to a preserved copy of 31 * bootstrap/kernel environment variables. We convert them to a 32 * dynamic array of strings later when the VM subsystem is up. 33 * 34 * We make these available through the kenv(2) syscall for userland 35 * and through kern_getenv()/freeenv() kern_setenv() kern_unsetenv() testenv() for 36 * the kernel. 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include <sys/types.h> 43 #include <sys/param.h> 44 #include <sys/proc.h> 45 #include <sys/queue.h> 46 #include <sys/lock.h> 47 #include <sys/malloc.h> 48 #include <sys/mutex.h> 49 #include <sys/priv.h> 50 #include <sys/kernel.h> 51 #include <sys/systm.h> 52 #include <sys/sysent.h> 53 #include <sys/sysproto.h> 54 #include <sys/libkern.h> 55 #include <sys/kenv.h> 56 57 #include <security/mac/mac_framework.h> 58 59 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); 60 61 #define KENV_SIZE 512 /* Maximum number of environment strings */ 62 63 /* pointer to the static environment */ 64 char *kern_envp; 65 static int env_len; 66 static int env_pos; 67 static char *kernenv_next(char *); 68 69 /* dynamic environment variables */ 70 char **kenvp; 71 struct mtx kenv_lock; 72 73 /* 74 * No need to protect this with a mutex since SYSINITS are single threaded. 75 */ 76 int dynamic_kenv = 0; 77 78 #define KENV_CHECK if (!dynamic_kenv) \ 79 panic("%s: called before SI_SUB_KMEM", __func__) 80 81 int 82 sys_kenv(td, uap) 83 struct thread *td; 84 struct kenv_args /* { 85 int what; 86 const char *name; 87 char *value; 88 int len; 89 } */ *uap; 90 { 91 char *name, *value, *buffer = NULL; 92 size_t len, done, needed, buflen; 93 int error, i; 94 95 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0")); 96 97 error = 0; 98 if (uap->what == KENV_DUMP) { 99 #ifdef MAC 100 error = mac_kenv_check_dump(td->td_ucred); 101 if (error) 102 return (error); 103 #endif 104 done = needed = 0; 105 buflen = uap->len; 106 if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2)) 107 buflen = KENV_SIZE * (KENV_MNAMELEN + 108 KENV_MVALLEN + 2); 109 if (uap->len > 0 && uap->value != NULL) 110 buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO); 111 mtx_lock(&kenv_lock); 112 for (i = 0; kenvp[i] != NULL; i++) { 113 len = strlen(kenvp[i]) + 1; 114 needed += len; 115 len = min(len, buflen - done); 116 /* 117 * If called with a NULL or insufficiently large 118 * buffer, just keep computing the required size. 119 */ 120 if (uap->value != NULL && buffer != NULL && len > 0) { 121 bcopy(kenvp[i], buffer + done, len); 122 done += len; 123 } 124 } 125 mtx_unlock(&kenv_lock); 126 if (buffer != NULL) { 127 error = copyout(buffer, uap->value, done); 128 free(buffer, M_TEMP); 129 } 130 td->td_retval[0] = ((done == needed) ? 0 : needed); 131 return (error); 132 } 133 134 switch (uap->what) { 135 case KENV_SET: 136 error = priv_check(td, PRIV_KENV_SET); 137 if (error) 138 return (error); 139 break; 140 141 case KENV_UNSET: 142 error = priv_check(td, PRIV_KENV_UNSET); 143 if (error) 144 return (error); 145 break; 146 } 147 148 name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK); 149 150 error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL); 151 if (error) 152 goto done; 153 154 switch (uap->what) { 155 case KENV_GET: 156 #ifdef MAC 157 error = mac_kenv_check_get(td->td_ucred, name); 158 if (error) 159 goto done; 160 #endif 161 value = kern_getenv(name); 162 if (value == NULL) { 163 error = ENOENT; 164 goto done; 165 } 166 len = strlen(value) + 1; 167 if (len > uap->len) 168 len = uap->len; 169 error = copyout(value, uap->value, len); 170 freeenv(value); 171 if (error) 172 goto done; 173 td->td_retval[0] = len; 174 break; 175 case KENV_SET: 176 len = uap->len; 177 if (len < 1) { 178 error = EINVAL; 179 goto done; 180 } 181 if (len > KENV_MVALLEN + 1) 182 len = KENV_MVALLEN + 1; 183 value = malloc(len, M_TEMP, M_WAITOK); 184 error = copyinstr(uap->value, value, len, NULL); 185 if (error) { 186 free(value, M_TEMP); 187 goto done; 188 } 189 #ifdef MAC 190 error = mac_kenv_check_set(td->td_ucred, name, value); 191 if (error == 0) 192 #endif 193 kern_setenv(name, value); 194 free(value, M_TEMP); 195 break; 196 case KENV_UNSET: 197 #ifdef MAC 198 error = mac_kenv_check_unset(td->td_ucred, name); 199 if (error) 200 goto done; 201 #endif 202 error = kern_unsetenv(name); 203 if (error) 204 error = ENOENT; 205 break; 206 default: 207 error = EINVAL; 208 break; 209 } 210 done: 211 free(name, M_TEMP); 212 return (error); 213 } 214 215 /* 216 * Populate the initial kernel environment. 217 * 218 * This is called very early in MD startup, either to provide a copy of the 219 * environment obtained from a boot loader, or to provide an empty buffer into 220 * which MD code can store an initial environment using kern_setenv() calls. 221 * 222 * When a copy of an initial environment is passed in, we start by scanning that 223 * env for overrides to the compiled-in envmode and hintmode variables. 224 * 225 * If the global envmode is 1, the environment is initialized from the global 226 * static_env[], regardless of the arguments passed. This implements the env 227 * keyword described in config(5). In this case env_pos is set to env_len, 228 * causing kern_setenv() to return -1 (if len > 0) or panic (if len == 0) until 229 * the dynamic environment is available. The envmode and static_env variables 230 * are defined in env.c which is generated by config(8). 231 * 232 * If len is non-zero, the caller is providing an empty buffer. The caller will 233 * subsequently use kern_setenv() to add up to len bytes of initial environment 234 * before the dynamic environment is available. 235 * 236 * If len is zero, the caller is providing a pre-loaded buffer containing 237 * environment strings. Additional strings cannot be added until the dynamic 238 * environment is available. The memory pointed to must remain stable at least 239 * until sysinit runs init_dynamic_kenv(). If no initial environment is 240 * available from the boot loader, passing a NULL pointer allows the static_env 241 * to be installed if it is configured. 242 */ 243 void 244 init_static_kenv(char *buf, size_t len) 245 { 246 char *cp; 247 248 for (cp = buf; cp != NULL && cp[0] != '\0'; cp += strlen(cp) + 1) { 249 if (strcmp(cp, "static_env.disabled=1") == 0) 250 envmode = 0; 251 if (strcmp(cp, "static_hints.disabled=1") == 0) 252 hintmode = 0; 253 } 254 255 if (envmode == 1) { 256 kern_envp = static_env; 257 env_len = len; 258 env_pos = len; 259 } else { 260 kern_envp = buf; 261 env_len = len; 262 env_pos = 0; 263 } 264 } 265 266 /* 267 * Setup the dynamic kernel environment. 268 */ 269 static void 270 init_dynamic_kenv(void *data __unused) 271 { 272 char *cp, *cpnext; 273 size_t len; 274 int i; 275 276 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 277 M_WAITOK | M_ZERO); 278 i = 0; 279 if (kern_envp && *kern_envp != '\0') { 280 for (cp = kern_envp; cp != NULL; cp = cpnext) { 281 cpnext = kernenv_next(cp); 282 len = strlen(cp) + 1; 283 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) { 284 printf( 285 "WARNING: too long kenv string, ignoring %s\n", 286 cp); 287 continue; 288 } 289 if (i < KENV_SIZE) { 290 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 291 strcpy(kenvp[i++], cp); 292 memset(cp, 0, strlen(cp)); 293 } else 294 printf( 295 "WARNING: too many kenv strings, ignoring %s\n", 296 cp); 297 } 298 } 299 kenvp[i] = NULL; 300 301 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 302 dynamic_kenv = 1; 303 } 304 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 305 306 void 307 freeenv(char *env) 308 { 309 310 if (dynamic_kenv && env != NULL) { 311 memset(env, 0, strlen(env)); 312 free(env, M_KENV); 313 } 314 } 315 316 /* 317 * Internal functions for string lookup. 318 */ 319 static char * 320 _getenv_dynamic(const char *name, int *idx) 321 { 322 char *cp; 323 int len, i; 324 325 mtx_assert(&kenv_lock, MA_OWNED); 326 len = strlen(name); 327 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 328 if ((strncmp(cp, name, len) == 0) && 329 (cp[len] == '=')) { 330 if (idx != NULL) 331 *idx = i; 332 return (cp + len + 1); 333 } 334 } 335 return (NULL); 336 } 337 338 static char * 339 _getenv_static(const char *name) 340 { 341 char *cp, *ep; 342 int len; 343 344 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 345 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 346 ; 347 if (*ep != '=') 348 continue; 349 len = ep - cp; 350 ep++; 351 if (!strncmp(name, cp, len) && name[len] == 0) 352 return (ep); 353 } 354 return (NULL); 355 } 356 357 /* 358 * Look up an environment variable by name. 359 * Return a pointer to the string if found. 360 * The pointer has to be freed with freeenv() 361 * after use. 362 */ 363 char * 364 kern_getenv(const char *name) 365 { 366 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 367 char *ret; 368 369 if (dynamic_kenv) { 370 if (getenv_string(name, buf, sizeof(buf))) { 371 ret = strdup(buf, M_KENV); 372 } else { 373 ret = NULL; 374 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 375 "getenv"); 376 } 377 } else 378 ret = _getenv_static(name); 379 return (ret); 380 } 381 382 /* 383 * Test if an environment variable is defined. 384 */ 385 int 386 testenv(const char *name) 387 { 388 char *cp; 389 390 if (dynamic_kenv) { 391 mtx_lock(&kenv_lock); 392 cp = _getenv_dynamic(name, NULL); 393 mtx_unlock(&kenv_lock); 394 } else 395 cp = _getenv_static(name); 396 if (cp != NULL) 397 return (1); 398 return (0); 399 } 400 401 static int 402 setenv_static(const char *name, const char *value) 403 { 404 int len; 405 406 if (env_pos >= env_len) 407 return (-1); 408 409 /* Check space for x=y and two nuls */ 410 len = strlen(name) + strlen(value); 411 if (len + 3 < env_len - env_pos) { 412 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); 413 env_pos += len+1; 414 kern_envp[env_pos] = '\0'; 415 return (0); 416 } else 417 return (-1); 418 419 } 420 421 /* 422 * Set an environment variable by name. 423 */ 424 int 425 kern_setenv(const char *name, const char *value) 426 { 427 char *buf, *cp, *oldenv; 428 int namelen, vallen, i; 429 430 if (dynamic_kenv == 0 && env_len > 0) 431 return (setenv_static(name, value)); 432 433 KENV_CHECK; 434 435 namelen = strlen(name) + 1; 436 if (namelen > KENV_MNAMELEN + 1) 437 return (-1); 438 vallen = strlen(value) + 1; 439 if (vallen > KENV_MVALLEN + 1) 440 return (-1); 441 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 442 sprintf(buf, "%s=%s", name, value); 443 444 mtx_lock(&kenv_lock); 445 cp = _getenv_dynamic(name, &i); 446 if (cp != NULL) { 447 oldenv = kenvp[i]; 448 kenvp[i] = buf; 449 mtx_unlock(&kenv_lock); 450 free(oldenv, M_KENV); 451 } else { 452 /* We add the option if it wasn't found */ 453 for (i = 0; (cp = kenvp[i]) != NULL; i++) 454 ; 455 456 /* Bounds checking */ 457 if (i < 0 || i >= KENV_SIZE) { 458 free(buf, M_KENV); 459 mtx_unlock(&kenv_lock); 460 return (-1); 461 } 462 463 kenvp[i] = buf; 464 kenvp[i + 1] = NULL; 465 mtx_unlock(&kenv_lock); 466 } 467 return (0); 468 } 469 470 /* 471 * Unset an environment variable string. 472 */ 473 int 474 kern_unsetenv(const char *name) 475 { 476 char *cp, *oldenv; 477 int i, j; 478 479 KENV_CHECK; 480 481 mtx_lock(&kenv_lock); 482 cp = _getenv_dynamic(name, &i); 483 if (cp != NULL) { 484 oldenv = kenvp[i]; 485 for (j = i + 1; kenvp[j] != NULL; j++) 486 kenvp[i++] = kenvp[j]; 487 kenvp[i] = NULL; 488 mtx_unlock(&kenv_lock); 489 memset(oldenv, 0, strlen(oldenv)); 490 free(oldenv, M_KENV); 491 return (0); 492 } 493 mtx_unlock(&kenv_lock); 494 return (-1); 495 } 496 497 /* 498 * Return a string value from an environment variable. 499 */ 500 int 501 getenv_string(const char *name, char *data, int size) 502 { 503 char *cp; 504 505 if (dynamic_kenv) { 506 mtx_lock(&kenv_lock); 507 cp = _getenv_dynamic(name, NULL); 508 if (cp != NULL) 509 strlcpy(data, cp, size); 510 mtx_unlock(&kenv_lock); 511 } else { 512 cp = _getenv_static(name); 513 if (cp != NULL) 514 strlcpy(data, cp, size); 515 } 516 return (cp != NULL); 517 } 518 519 /* 520 * Return an integer value from an environment variable. 521 */ 522 int 523 getenv_int(const char *name, int *data) 524 { 525 quad_t tmp; 526 int rval; 527 528 rval = getenv_quad(name, &tmp); 529 if (rval) 530 *data = (int) tmp; 531 return (rval); 532 } 533 534 /* 535 * Return an unsigned integer value from an environment variable. 536 */ 537 int 538 getenv_uint(const char *name, unsigned int *data) 539 { 540 quad_t tmp; 541 int rval; 542 543 rval = getenv_quad(name, &tmp); 544 if (rval) 545 *data = (unsigned int) tmp; 546 return (rval); 547 } 548 549 /* 550 * Return an int64_t value from an environment variable. 551 */ 552 int 553 getenv_int64(const char *name, int64_t *data) 554 { 555 quad_t tmp; 556 int64_t rval; 557 558 rval = getenv_quad(name, &tmp); 559 if (rval) 560 *data = (int64_t) tmp; 561 return (rval); 562 } 563 564 /* 565 * Return an uint64_t value from an environment variable. 566 */ 567 int 568 getenv_uint64(const char *name, uint64_t *data) 569 { 570 quad_t tmp; 571 uint64_t rval; 572 573 rval = getenv_quad(name, &tmp); 574 if (rval) 575 *data = (uint64_t) tmp; 576 return (rval); 577 } 578 579 /* 580 * Return a long value from an environment variable. 581 */ 582 int 583 getenv_long(const char *name, long *data) 584 { 585 quad_t tmp; 586 int rval; 587 588 rval = getenv_quad(name, &tmp); 589 if (rval) 590 *data = (long) tmp; 591 return (rval); 592 } 593 594 /* 595 * Return an unsigned long value from an environment variable. 596 */ 597 int 598 getenv_ulong(const char *name, unsigned long *data) 599 { 600 quad_t tmp; 601 int rval; 602 603 rval = getenv_quad(name, &tmp); 604 if (rval) 605 *data = (unsigned long) tmp; 606 return (rval); 607 } 608 609 /* 610 * Return a quad_t value from an environment variable. 611 */ 612 int 613 getenv_quad(const char *name, quad_t *data) 614 { 615 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 616 char *vtp; 617 quad_t iv; 618 619 if (!getenv_string(name, value, sizeof(value))) 620 return (0); 621 iv = strtoq(value, &vtp, 0); 622 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) 623 return (0); 624 switch (vtp[0]) { 625 case 't': case 'T': 626 iv *= 1024; 627 case 'g': case 'G': 628 iv *= 1024; 629 case 'm': case 'M': 630 iv *= 1024; 631 case 'k': case 'K': 632 iv *= 1024; 633 case '\0': 634 break; 635 default: 636 return (0); 637 } 638 *data = iv; 639 return (1); 640 } 641 642 /* 643 * Find the next entry after the one which (cp) falls within, return a 644 * pointer to its start or NULL if there are no more. 645 */ 646 static char * 647 kernenv_next(char *cp) 648 { 649 650 if (cp != NULL) { 651 while (*cp != 0) 652 cp++; 653 cp++; 654 if (*cp == 0) 655 cp = NULL; 656 } 657 return (cp); 658 } 659 660 void 661 tunable_int_init(void *data) 662 { 663 struct tunable_int *d = (struct tunable_int *)data; 664 665 TUNABLE_INT_FETCH(d->path, d->var); 666 } 667 668 void 669 tunable_long_init(void *data) 670 { 671 struct tunable_long *d = (struct tunable_long *)data; 672 673 TUNABLE_LONG_FETCH(d->path, d->var); 674 } 675 676 void 677 tunable_ulong_init(void *data) 678 { 679 struct tunable_ulong *d = (struct tunable_ulong *)data; 680 681 TUNABLE_ULONG_FETCH(d->path, d->var); 682 } 683 684 void 685 tunable_int64_init(void *data) 686 { 687 struct tunable_int64 *d = (struct tunable_int64 *)data; 688 689 TUNABLE_INT64_FETCH(d->path, d->var); 690 } 691 692 void 693 tunable_uint64_init(void *data) 694 { 695 struct tunable_uint64 *d = (struct tunable_uint64 *)data; 696 697 TUNABLE_UINT64_FETCH(d->path, d->var); 698 } 699 700 void 701 tunable_quad_init(void *data) 702 { 703 struct tunable_quad *d = (struct tunable_quad *)data; 704 705 TUNABLE_QUAD_FETCH(d->path, d->var); 706 } 707 708 void 709 tunable_str_init(void *data) 710 { 711 struct tunable_str *d = (struct tunable_str *)data; 712 713 TUNABLE_STR_FETCH(d->path, d->var, d->size); 714 } 715